Field of the Invention
The present invention relates to a three-dimensional composite tape usable in particular to form the topsheet of absorbent sanitary articles. The invention also relates to a method and an apparatus for producing a three-dimensional composite tape.
Description of Prior Art
The topsheet of absorbent sanitary articles is usually formed of a sheet of permeable material, generally fibrous, typically of non-woven fabric, configured to transfer body fluids toward an absorbent core encased between the topsheet and a backsheet impermeable to body fluids.
In more traditional solutions, the topsheet of an absorbent sanitary article is formed of a smooth sheet. There are also known composite sheets with a three-dimensional structure intended to form the topsheet of absorbent sanitary articles. For example, EP-A-1419754 describes a composite sheet comprising an upper layer and a lower layer, both made of an essentially inextensible sheet, which are partially welded together at a large number of welds. The upper layer forms a large number of hollow protrusions in the areas different from the welds, formed by reliefs of the upper layer that enclose respective empty volumes. The lower layer has a flat shape. The formation of the hollow projections of the upper layer is obtained by subjecting the upper layer to an embossing step prior to the mutual welding between the upper layer and the lower layer.